Waterflooding is commonly used in the secondary recovery of oil. The water used for waterflooding is usually obtained from source wells or bodies of water such as seas which may contain corrodents such as hydrogen sulfide, carbon dioxide, oxygen and salts of the alkali and alkaline metals. The presence of such corrodents in an aqueous solution at temperatures of 100.degree.-190.degree. F often results in rapid deterioration of steel pipelines. A corrosion inhibitor is needed to reduce the corrosion rate to a minimum in such systems. Futhermore, when there is apparent formation plugging as a result of using dispersible inhibitors, a water soluble inhibitor is most desirable as a corrosion inhibitor in waterflood systems.
It is known in the prior art that heterocyclic nitrogen compound derivatives such as quaternary derivatives of polyalkylpyridines are important compounds when quaternized of corrosion inhibiting compositions. See for instance, U.S. Pat. Nos. 3,066,097 and 3,033,784.
It is also known from the art and is disclosed in the above U.S. Pat. No. 3,033,784 that the quaternized polyalkylpyridines should be used in combination with ethoxylated alcohol derivatives of fatty acids.
Nevertheless, it has not been generally realized how to use heterocyclic nitrogen derivatives other than quaternary derivatives in combination with suitable surfactants, such as sorbital monooleate oxyethylene condensation products to produce soluble corrosion inhibitors as opposed to the dispersions of the art.